Light-sensitive photographic element



d vs9 9 a f 1 2,043,905

UNl'lEYDi' STATES. PAT

H Eastman Kodak Company, Rochester, N. Y a

Merrill'W. Seymour, mm, N- Y., aulrn r corporation of New York a e No Drawing. Application January 1;, 19:5,

a swarms-n woman.wits-=1) This invention relates to photographic materials have been used in producing bichromated rials and more particularly to films of which the layers and that they are not, only capable of use, I light-sensitive portion consists of a bichromated for all, of the above-mentioned'purposes for which 1 layer comprising an ester or mixed ester of a known materials have been employei but are 5 polybasic organicacid with cellulose. g 7 also susceptible of use in afnumber, of processu 5 Bichromatedlayers of various colloids have for which known rnaterials are wholly unsuited, long been known and used for the production of In the following examplesand description I photomechanical resists and for similar purposes. have set forth several of thepreferred Tembodi-' Gelatin,.gl'ue and shellac have been the materials ments of my invention, but it is to be understood 0 most commonly employed, but all of these posses Ethat t ey i c d merely P 'D RS 10 certain inherent disadvantages, As is. well illustration and not as a' limitation thereof. known, when a bichromated gelatin layer, for ex'-.- As indicated above, the esters of cellulose which r e ample, is exposedto light, theexposed portions I have found particularly suitable for the pure oi the gelatin are,insolubilized, -while the unexposes of my invention are those aerivearm poly- 1 posed portions are unaffected andmay be washed 1 basic organic acids, such as phthalic, tartaric, and away, leaving a relief image of the object photocitric acids and,in fact, almostany of the poly graphed. Such gelatin relief images, however, basic organic acids. which fwill give a cellulose I are not satisfactory ,foruse in certain photo- H ester havinga free carboxyl group in its'moleculeff engraving processes employing the etching. sof Of these. I have found the mixed organic esters o metals by acids,on account of the permeability of' of cellulose, such as cellulose acetate .phthalate,

gelatin to aqueous solutions of acids and other cellulose acetate citrate,:and celluloseacetate, reagents used. for etching. I n other instances, succinate and thelike are particularlydesirable I such as certain color hotographic pro ss s in n du s y mproved light-sensitive colloid I where a dye or other material is employed for layers. These esters may be prepared by the 5 producing a colored image, it is frequently necestechnique described in the ,co-pending applicasary to add to or to form in the gelatin mordant tion of C. J. Malm ,and-C.'R,. Waring, serial No, j ing agents, but this is disadvantagfeousbeoause 380,252,,flled July 22, l9 29and comprising the, these added materials have a pronounced tend: 7 treatment of apartially acetylated cellulose, such, .1 ency to absorb light and thus .toalter the hue for-example, as a cellulose acetate preparedas,

30 and/or transparency of the dye image. described in U. S. Patent""1,669,9 44 f (':1a,'rk'

The principal object ofthe present invention and Malm or a partially hydrolyzed cellulose is to overcome the limitations of. the prior art maf acetate, with a dicarboxyflci-acld anhydflde, V I terials above referred to and to provide a light the presence. of an or n base. Such as pyridine,

sensitive photographic element which can be em quinoline, V and other salt forming oi this a5 ployed both for the production of relief images character. As previously stated, these a5:

and transparencies and for the production of esters are distinguished by the presence of; free, e v I photomechanical resists adapted for, use in carboxyl group in the molecule, the pres nc photoengraving processes. ;A still further object. this group rendering them readily susceptible of, isto provide alight-sensitivephotographic mateconversion into water-soluble compounds by.

40 rial which is adapted; for invasions color treatment of the mixed ester withappropriatefio photographic processes and in which the neces- I hydroxides; such asthose'of ammonium, sodiiun, f city for introducing .mordants for holding the potassium, and the like, some of these ester-sin color in, the image layer isobviate'd. Another theiracidform being substantially insoluble Lin object is to'produce a photomechanical resist water. Other polybasic aci osters of eu 1',

which! ay be'used in the etching of metals by a whichare characterized by the presence ofafreegfl meansof acids or oxidizingsolutions. Other obcarboxyl group, such as cellulose phthalate, cel jects will appear hereinafter. 'lulose citrate and cellulose succlnate, may-"like- These obJects'are; accomplished by the follow wise be employed. a

ing invention which, in its broadest'aspects, com- The technique employed for producing a prises the employment'as the light-sensitive ma-- sensitive layer in accordance with myzinvention m terial' of abichromated' layer comprising an ester is fairly simple and comprises, first making up a;

or mixed esterofa polybaslc organic acid with solution .of the desired ester in, an appropriate cellulose. I have found that. these cellulose esters i solvent, Cellulose acetate phthalate; for, 62-1; 5 5 maybe employed in substantially the same way ample, may bedissolved in low concentration in that gelatin, shellac, and other colloidal matea mixture of equal parts by weight of acetone 66 ent invention, on the contrary, are susceptible of such use since acid has no deleterious eflect upon the cellulose ester material and, in fact, tends to render it even more insoluble and impermeable. Another outstanding advantage of the cellulose esters herein described is the fact that there is no necessity for the use of mordants therewith as is frequently the case with gelatin and similar resists in order to obtain the proper mordanting or anchoring of the coloring material in the colloid layer, a basic dye, for example, tending to react with the free carboxyl of the cellulose esters herein described and thereby chemically uniting with the colloid itself. It will thus be seen that a resist consisting oi cellulose acetate phthalate or other mixed acidester of cellulose is highly satisfactory because of the fact that it is itself reactive with respect to the dye and there is no necessity of using mordants which, as indicated, have a tendency to absorb light and thus degrade the color of the image.

The materials of the present invention are also especially adaptable for use in certain color photographic processes, and in the manufacture of various types of screens comprising minute colored elements for color photography by the screen film or screen plate processes.

For the preparation of a photoengraving resist, cellulose acetate phthalate is undoubtedly the best oi the esters mentioned above on account of the relative impermeability of this material in its free acid form to aqueous solutions.

I have also discovered a unique property of cellulose acetate citrate; If this material is very thinly coated, for example, about 3 c. c. of solution per 5"x7" plate, and allowed to stand for several days after drying and before using, a wash-ofl image is not obtained with the procedure herein described. Instead, a general insolubilization of the layer takes place, the exposed portions tend to repel basic dyes in dilute acid solution, while the unexposed portions take them up so that a negative image is produced in printing from a negative somewhat as in the pinatype process.

What I claim is:

1. A light sensitive photographic element com prising a bichromated layer composed of a cellulose organic ester having free carboxyl groups.

2. A light sensitive photographic element comprising a bichromated layer composed of a mixed organic ester of cellulose having Jree carboxyl groups.

3. A light sensitive photographic element comprising a bichromated layer composed of a mixed organic ester of cellulose comprising acyl groups lose acetate phthalate, said layer containing a of a monobasie organic ester and acyl groups of a polybasic organic acid, said last mentioned apyl groups'having a free carboxyl group.

4. A light sensitive photographic element com prising abichromated layer composed of a mixed 5 organic ester of cellulose, said ester containing acetyl groups and acyl groups of a polybasic organic ester having a free carboxyl group.

5. A light sensitive photographic element comprising a bichromated layer composed of cellulose acetate phthalate.

6. A light sensitive photographic element com prising a bichromated layer composed of cellulose acetate citrate. I

7. A light sensitive photographic element com prising a bichromated layer composed of cellulose acetate succinate.

8. A light sensitive photographic element comprising a bichromated layer composed of 'a cellulose organic ester having free carboxyl groups, said layer. comprising a basic dye chemically united to the cellulose organic ester material.

9. A light sensitive photographic element comprising a bichromated layer composed of cellu- 25 basic dye chemically united to the cellulose acetate phthalate layer.

10. A photographic printing plate comprising a support having thereon an image-bearing layer, the image portion of which is composed of a mixed celllulose organic ester having free carboxyl groups in its molecules, said portion being insoluble in, and substantially impermeable to, water and aqueous acid solutions.

11. A photographic printing plate comprising a 35 support having thereon an image-bearing layer,

13. A photoengraving resist adapted for use 50 V with strongly acid etching solutions comprising a support, having a relief image thereon, said image consisting of an insolubilized cellulose acetate phthalate.

MERRILL W. SEYMOUR. 

